Gas Trip Calculator
Estimate your road trip fuel cost: enter the distance, your car's MPG, and the gas price to see gallons needed and total cost.
Planning a drive? Our free gas trip calculator estimates exactly what the fuel will cost before you leave. Enter the one-way distance, your car's fuel economy, and the current gas price — tick 'round trip' to double it — and get the total fuel cost, gallons needed, and total miles instantly.
How to use this calculator
- Enter the one-way driving distance in miles.
- Enter your car's real-world MPG (measure it with the MPG calculator).
- Enter the current price per gallon where you'll be driving.
- Tick 'round trip' if you're coming back the same way, then press Calculate.
The formula
Gallons = distance ÷ MPG; fuel cost = gallons × price per gallon
Worked example
A 300-mile drive at 25 MPG and $3.50 per gallon needs 12 gallons and costs $42.00 one-way — $84.00 round trip.
Frequently Asked Questions
How accurate is this fuel cost estimate?
Very close for highway driving, since the math is exact: distance ÷ MPG × price per gallon. The main uncertainty is your MPG — use your real-world figure (measure it with our MPG calculator) rather than the EPA sticker, and add 10–15% if you expect heavy traffic or mountain roads. Gas prices also vary along the route, so check prices at your destination.
Should I use the EPA MPG or my real MPG?
Always use your real MPG. EPA ratings are measured in a lab under standardized cycles, and most drivers get 10–20% less in the real world, especially with city driving, roof cargo, or aggressive acceleration. Track a few tanks with the MPG calculator for the most accurate trip budget.
How do I budget for a multi-stop road trip?
For trips with several stops, use our road trip calculator instead — it lets you enter each leg separately and totals the fuel cost, miles, and drive time. For a simple A-to-B drive with the same car the whole way, this calculator is all you need.
What gas price should I enter?
Enter the average price you expect to pay along the route. Prices vary by state — sometimes by more than a dollar per gallon — so a quick check of current prices at your destination state gives a better estimate than your home price alone. Apps like GasBuddy show live station prices along your route.